The invention relates to slats from which shutters for doors or windows can be assembled. More specifically, the invention concerns louvre shutters which comprise a rectangular frame in which the slats are rotatably journalled. The so composed shutter may be hingedly connected to the door, window-frame, or may be horizontally slidable in top and bottom rails. The shutters are intended to give protection from light, rain and wind in closed position, and variable light and air influx through adjustment of slat position, and also as protection against unauthorized entry.
The earliest shutters of such type had been made of wood. Such shutters could well serve as a protection against sunlight, and in order to be burglary proof had to be very thick, thus heavy and expensive. A further disadvantage of wooden shutters had been that they required much maintenance by frequent painting, but in spite of that, warping and deterioration due to climatic conditions, could not be prevented.
It has been suggested--and practised to a certain extent--to make slats out of aluminium. The aluminium slats were hollow bodies manufactured by means of an extrusion process which did withstand climatic influence, particularly when anodized, but aluminium slats are most expensive.
Finally, there are known plastic slats which are manufactured also by means of an extrusion process. These are not weatherproof, and are rather weak: they can be easily broken thus giving access to an unauthorized person into the room where shutters made of such slats had been installed. Moreover, these slats are easily bendable, and a person seeking entrance into a room through a door on which a shutter of plastic slats had been provided, needs only to exert pressure from the outside of the slat, bending it so that it bulges inwardly, and as a consequence is forced out of its frame.
Where this has been done to a number of slats, these are no longer held in position, and the shutter as a whole, no longer bars entrance into the room.